Boot with the upgrade DVD, start the installer, do not enter your product
key. Select the correct version for your Product Key (this is important, do
not select a different version). Run setup. Once completed, now you get to
reinstall as an upgrade, this time using your purchased Product Key.
Basically you get to do it twice. Try not to get infected this time, and if
you do, learn how to clean it without doing things the hard way.
Best of Luck,
Rick Rogers, aka "Nutcase" - Microsoft MVP
Windows help - www.rickrogers.org
My thoughts http://rick-mvp.blogspot.com
"gavin_996" <email@example.com> wrote in message
> So I had a virus on my computer after i had upgraded my computer to vista
> bought the upgrade version and it wont let me install it from the disk
> because i had to format my drive and i no longer have a os so i cant
> it but my mom has windows xp so can i install it to my computer without
> activating it and then in stall vista. Please help.